The present invention relates to apparatuses and methods for protecting shorelines or urban areas along waterways against periodic high water levels associated with tidal surges or high level floodwaters. More particularly, the present invention relates to a tidal responsive barrier that includes a collapsible high-strength tensile membrane anchored at a bottom end to a sea or river bed and having bladders in a top end of the membrane, where the bladders may be selectively inflated to cause the leading edge of the membrane to rise to the surface of the sea or rive water (e.g., in response to a tidal change) such that the membrane stretches from the sea or river bed to the water surface and to water's edge where the membrane is anchored to structural pylons.
The principle threat of flooding in the next century is not necessarily from the rise in the sea level itself, but from the increase in extremes during high tides and storms which create breaches of existing flood defenses for relatively brief periods. Permanent levees, jetties or groins have been previously employed to protect shorelines and offer some protection against such periodic extremes in high tides or storms; however, these devices typically comprise concrete blocks, rip-rap or other heavy weighted, fortifying materials that are permanent structures that do not enable passage of marine vehicles, inhibit natural marine ecosystems, inhibit full enjoyment of the region of the shoreline and are expensive to build and deploy.
One prior art groin structure that utilizes a floating mesh net secured to a seabed for protecting a shore line is described in US Publication No. US 2005/0036839. This prior art groin structure employs floatation supports such as air filled bladders, polyethylene floats or other materials to stretch the mesh net between the seabed and a low tide level 36. At high tide levels the mesh net of the groin structure is completely immersed in the water and thus, not capable of effectively inhibiting periodic extreme tidal changes or surges from flooding the shoreline. Moreover, the disclosed prior art groin structure is disclosed as being permanently deployed, which presents similar problems for inhibiting passage of marine vehicles, marine life, and the full enjoyment of the region of the shoreline where the groin structure is deployed.
Thus, there is a need for a tidal barrier that overcomes the problems noted above and is responsive to periodic high water levels associated with tidal surges or high level floodwaters to protect shorelines or urban areas along waterways from such periodic high water levels.